/*
 *    Copyright 2011-2012 The Hook Team
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package org.hook.core.util;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;

/**
 * 提供调用getter/setter方法，访问私有变量，调用私有方法，获取泛型类型Class，被AOP过的真实类等工具函数。
 * 
 * @author suwuqiang 2011-8-19
 */
public abstract class ReflectionUtil {
	private static Logger logger = LoggerFactory.getLogger(ReflectionUtil.class);
	public static final String CGLIB_CLASS_SEPARATOR = "$$";

	/**
	 * 调用Getter方法
	 * 
	 * @param obj
	 * @param propertyName
	 * @return Object
	 */
	public static Object invokeGetterMethod(Object obj, String propertyName) {
		String getterMethodName = "get" + StringUtils.capitalize(propertyName);
		return invokeMethod(obj, getterMethodName, new Class[] {}, new Object[] {});
	}

	/**
	 * 调用Setter方法 使用value的Class来查找Setter方法
	 * 
	 * @param obj
	 * @param propertyName
	 * @param value
	 */
	public static void invokeSetterMethod(Object obj, String propertyName, Object value) {
		invokeSetterMethod(obj, propertyName, value, null);
	}

	/**
	 * 调用Setter方法
	 * 
	 * @param obj
	 * @param propertyName
	 * @param value
	 * @param propertyType
	 */
	public static void invokeSetterMethod(Object obj, String propertyName, Object value, Class<?> propertyType) {
		Class<?> type = propertyType != null ? propertyType : value.getClass();
		String setterMethodName = "set" + StringUtils.capitalize(propertyName);
		invokeMethod(obj, setterMethodName, new Class[] { type }, new Object[] { value });
	}

	/**
	 * 直接读取对象属性值，忽略private/protected修饰符(不通过getter函数)
	 * 
	 * @param obj
	 * @param fieldName
	 * @return Object
	 */
	public static Object getFieldValue(final Object obj, final String fieldName) {
		Field field = getAccessibleField(obj, fieldName);
		if (field == null) {
			throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + obj + "]");
		}
		Object result = null;
		try {
			result = field.get(obj);
		} catch (IllegalAccessException e) {
			logger.error("不可能抛出的异常{}", e.getMessage());
		}
		return result;
	}

	/**
	 * 直接设置对象属性值，忽略private/protected修饰符(不通过setter函数)
	 * 
	 * @param obj
	 * @param fieldName
	 * @param value
	 */
	public static void setFieldValue(final Object obj, final String fieldName, final Object value) {
		Field field = getAccessibleField(obj, fieldName);
		if (field == null) {
			throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + obj + "]");
		}
		try {
			field.set(obj, value);
		} catch (IllegalAccessException e) {
			logger.error("不可能抛出的异常:{}", e.getMessage());
		}
	}

	/**
	 * 循环向上转型， 获取对象的DeclaredField，并强制设置为可访问 如向上转型到Object仍无法找到，返回null
	 * 
	 * @param obj
	 * @param fieldName
	 * @return
	 */
	public static Field getAccessibleField(final Object obj, final String fieldName) {
		Assert.notNull(obj, "object不能为空");
		Assert.hasText(fieldName, "fieldName");
		for (Class<?> superClass = obj.getClass(); superClass != Object.class; superClass = superClass.getSuperclass()) {
			try {
				Field field = superClass.getDeclaredField(fieldName);
				field.setAccessible(true);
				return field;
			} catch (NoSuchFieldException e) {// NOSONAR
				// Field不在当前类定义,继续向上转型
			}
		}
		return null;
	}

	/**
	 * 对于被cglib AOP过的对象， 取得真实的Class类型
	 * 
	 * @param clazz
	 * @return
	 */
	public static Class<?> getUserClass(Class<?> clazz) {
		if (clazz != null && clazz.getName().contains(CGLIB_CLASS_SEPARATOR)) {
			Class<?> superClass = clazz.getSuperclass();
			if (superClass != null && !Object.class.equals(superClass)) {
				return superClass;
			}
		}
		return clazz;
	}

	/**
	 * 直接调用对象方法，忽略private/protected修饰符(用于一次性调用的情况)
	 * 
	 * @param obj
	 * @param methodName
	 * @param parameterTypes
	 * @param args
	 * @return Object
	 */
	public static Object invokeMethod(final Object obj, final String methodName, final Class<?>[] parameterTypes, final Object[] args) {
		Method method = getAccessibleMethod(obj, methodName, parameterTypes);
		if (method == null) {
			throw new IllegalArgumentException("Could not find method [" + methodName + "] on target [" + obj + "]");
		}
		try {
			return method.invoke(obj, args);
		} catch (Exception e) {
			throw convertReflectionExceptionToUnchecked(e);
		}
	}

	/**
	 * 循环向上转型，获取对象的DeclaredMethod，并强制设置为可访问。
	 * 
	 * 如向上转型到Object仍无法找到，返回null。
	 * 
	 * 用于方法需要被多次调用的情况，先使用本函数先取得Method，然后调用Method.invoke(Object obj, Object...
	 * args)
	 * 
	 * @param obj
	 * @param methodName
	 * @param parameterTypes
	 * @return Method
	 */
	public static Method getAccessibleMethod(final Object obj, final String methodName, final Class<?>... parameterTypes) {
		Assert.notNull(obj, "object不能为空");
		for (Class<?> superClass = obj.getClass(); superClass != Object.class; superClass = superClass.getSuperclass()) {
			try {
				Method method = superClass.getDeclaredMethod(methodName, parameterTypes);
				method.setAccessible(true);
				return method;
			} catch (NoSuchMethodException e) {// NOSONAR
				// Method不在当前类定义,继续向上转型
			}
		}
		return null;
	}

	/**
	 * 通过反射，获得Class定义中声明的父类的泛型参数的类型。如无法找到，返回Object。
	 * 
	 * eg. public UserDao extends HibernateDao<User>
	 * 
	 * @param <T>
	 * @param clazz
	 * @return Class
	 */
	public static Class<?> getSuperClassGenricType(final Class<?> clazz) {
		return getSuperClassGenricType(clazz, 0);
	}

	/**
	 * 通过反射，获得Class定义中声明的父类的泛型参数的类型。如无法找到，返回Object。
	 * 
	 * @param clazz
	 * @param index
	 * @return Class
	 */
	public static Class<?> getSuperClassGenricType(final Class<?> clazz, final int index) {
		Type genType = clazz.getGenericSuperclass();
		Class<?> c = Object.class;
		if (!(genType instanceof ParameterizedType)) {
			logger.warn(clazz.getSimpleName() + "'s superclass not ParameterizedType");
			return c;
		}
		Type[] params = ((ParameterizedType) genType).getActualTypeArguments();
		if (index >= params.length || index < 0) {
			logger.warn("Index: " + index + ", Size of " + clazz.getSimpleName() + "'s Parameterized Type: " + params.length);
			return c;
		}
		if (!(params[index] instanceof Class)) {
			logger.warn(clazz.getSimpleName() + " not set the actual class on superclass generic parameter");
			return c;
		}
		return (Class<?>) params[index];
	}

	public static RuntimeException convertReflectionExceptionToUnchecked(Exception e) {
		return ExceptionUtil.unchecked(e);
	}
}
